An object moving in a curve

Curve

In mathematics, a curve is, generally speaking, an object similar to a line but which is not required to be straight...

d path is called Curvilinear motion.
Example:A stone

STONe

is a Japanese manga written and illustrated by Sin-Ichi Hiromoto. Kodansha released the two bound volumes of the manga on April 23, 2002 and August 23, 2002, respectively.The manga is licensed for an English-languague released in North America be Tokyopop...

 thrown into the air in an angle

Angle

In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...

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Curvilinear motion describes the motion of a moving particle that conforms to a known or fixed curve. The study of such motion involves the use of two such co-ordinate systems with the first being Planar motion and the latter being Cylindrical Motion.

Planar Motion

In planar motion, the velocity and acceleration components of the particle are always tangential and normal to the fixed curve. The Velocity is always tangential to the curve and the acceleration can be broken up into both a tangential and normal component.

Cylindrical Components

With Cylindrical co-ordinates, the motion is best described in polar form with components that resemble polar vectors. As with Planar motion, the velocity is always tangential to the curve, but in this form can consist of different intermediate components that can now run along the radius and its normal vector. This type of co-ordinate system is best used when the motion is restricted to the plane upon which it travels.